Publication of Registered Japanese Utility Model Application No. 3057990 discloses a shelf board locking structure that includes a post in which a plurality of annular locking grooves are formed in its outer circumferential surface in the longitudinal direction at given intervals, a tapered sleeve that is attached to the outer circumferential surface of the post in a state in which a protrusion formed on the inner circumferential surface is fitted into the locking groove of the post, and is formed so that the diameter of the external shape thereof gradually increases downward, and a shelf board that has an inner surface shape that gradually increases in diameter downward to approximately coincide with part or the entirety of the outer surface shape of the tapered sleeve, and has a ring that is provided at each corner and is disposed around the outer circumferential surface of the tapered sleeve that is attached to the outer circumferential surface of the post, wherein the right and left rings of the shelf board differ in height, and are alternately disposed around the outer circumferential surface of the tapered sleeve, and right and left shelf boards can be connected by utilizing a single post.
Publication of Registered Japanese Utility Model Application No. 3066571 discloses a metal rack that includes four posts in which grooves are formed in the circumferential direction at equal intervals, and a shelf, and utilizes a tapered sleeve that that can be vertically divided in two, includes a protrusion that extends in the circumferential direction and is fitted into a groove that is formed in the post and extends in the circumferential direction, and is secured at an appropriate position in the direction of the height of the post, and a tapered sleeve that has a vertical cut so that the post can be inserted into the tapered sleeve from the side, and is disposed over the tapered sleeve that is secured on the post, wherein the shelf is installed by integrally securing the tapered sleeve on part of the shelf, and disposing the secured tapered sleeve over the tapered sleeve that is secured on the post, the shelf may be a shelf that integrally includes a crosspiece and a tabular shelf main body, wherein a tapered sleeve is secured at each corner of the crosspiece, a shelf that includes a pair of crosspieces on which a tapered sleeve is secured at each end in the longitudinal direction and which are suspended on the posts in the widthwise direction of the rack, and a shelf main body that is separately formed from the crosspieces, is suspended on the crosspieces movably in the longitudinal direction, and has a width equal to half the total width of the shelf, and a shelf that includes a pair of crosspieces on which a tapered sleeve is secured at each end in the longitudinal direction and which are suspended on the posts in the widthwise direction of the rack, and a shelf main body that is separately formed from the crosspieces, is suspended on the crosspieces movably in the longitudinal direction, and has a length equal to half the length of the shelf, and these shelves are appropriately used in combination.
According to the above assembly shelves, a single post can be shared when connecting two shelf board members in the longitudinal direction. This implements easy assembly while providing a good design.    (Patent Document 1) Publication of Registered Japanese Utility Model Application No. 3057990    (Patent Document 2) Publication of Registered Japanese Utility Model Application No. 3066571